As portable electronic devices become more compact, and the amount of information to be processed and stored increases, it has become a significant challenge to design a user interface that allows users to easily interact with the device. This is unfortunate because the user interface is the gateway through which users receive not only content but also responses to user actions or behaviors, including user attempts to access a device's features or tools. Some portable electronic devices (e.g., mobile telephones, sometimes called mobile phones, cell phones, cellular telephones, and the like) have resorted to adding more pushbuttons, increasing the density of push buttons, overloading the functions of pushbuttons, or using complex menu systems to allow a user to access, store and manipulate data. These conventional user interfaces often result in complicated key sequences and menu hierarchies that must be memorized by the user.
The interfaces for entering text that are currently available suffer the same shortcomings. Users of portable devices often have to enter text using keys or buttons that are overloaded with multiple letters or with buttons that do not correspond to any letter in particular. With these keys or buttons, entering just one letter can take multiple key or button presses. This makes the text entry process cumbersome and inefficient.
Accordingly, there is a need for more efficient interfaces for entering text on a portable device.